One of the most difficult shapes to create with a 3D printer is a sphere.
Spheres are difficult for several reasons.
Secondly, spheres have a lot of overhangs that need support.
Here you can see the effect that the labeled layer heights have on the stair-stepped appearance. Image courtesy ofhttp://3dprototypesandmodels.com.au/3d-printing-terminology-specifications/
Thirdly, FDM printers end up leaving visible layer lines when printing curves that cross the Z-axis.
It is possible to address these issues; however, each fix comes with its own compromise too.
The brim or raft helps to secure your print while the support structures keep the overhangs from drooping.
A brim is almost identical, but it only touches the print at the edges and doesnt go underneath.
A raft is typically more difficult to remove due to the increased contact area.
Both options are intended to be cut away during post-processing.
Support structures work well with rafts and brims as they can connect to them easily.
They are designed to provide support to extreme overhangs to prevent drooping.
Again, these need to be removed during post-processing.
Support structures, rafts, and brims all leave some artifacts on the spheres surface where they contact.
Even if theyre removed carefully, the artifacts will need to be smoothed.
This eliminates the need for a raft, brim, or support structures.
Unfortunately, it does mean that you better glue the two pieces back together once theyre printed.
You will generally need to smooth any unevenness that you see at the joint of the sphere.
Its a good idea to print the two halves separately.
Doing so reduces the height of each step, making them less distinct and needing less smoothing in post-processing.
Here you’re free to see the effect that the labeled layer heights have on the stair-stepped appearance.
Image courtesy ofhttp://3dprototypesandmodels.com.au/3d-printing-terminology-specifications/
